Bicycle frame



FIG. 1 is a left side elevation view of a bicycle frame showing the new design with the right side elevation view being a mirror-image thereof.

FIG. 2 is detailed close-up view of the spring associated with the bicycle frame.

FIG. 3 is top plan view of the bicycle frame.

FIG. 4 is a bottom plan view of the bicycle frame.

FIG. 5 is a front elevation view of the bicycle frame; and,

FIG. 6 is rear elevation view of the bicycle frame. 

I claim the ornamental design for a bicycle frame, as shown and described. 